LOOKING FOR SIMPLE AIRFOIL SHAPED PLASTIC!

[jplot]

I am searching for any plastic extruder that might be producing an airfoil shape (as in autogiro rotors---flat on bottom). My concerns are for model type autogiros and would have a width of 1 inch to 4 inches.

 

[nbucska]

you should specifythe material or at least its properties
and quantity per year .

<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[jplot]

My research on plastic, which has been mostly done on the internet, makes me realize that there are many different types and many different processes and for me to even try to learn enough to become an expert would be folly. I would have to leave my project of rotor pursuit which has brought me to plastics in the first place.
Actually my search is for any kind of material that just might be being mass produced (and therefore much more likely to be reasonably priced) in something close to an airfoil shape. I guess I have my own modus operandi which has worked for me all my life and no matter what the real engineers say I am going to stick with it.

 

[dwightdixon]

Look to the other manufacturers of auto gyro models. They get their parts from somewhere. This particular forum site is mostly engineering problems and answers. This is not a good place to bad mouth conventional engineers and their ways of doing business. They are successful in doing what they do also. Most of the things you use in your life were designed and made by engineers. If you do not want to use good engineering techniques, you might find youself living in the woods cooking over an open fire.

Try a search on the hobby website

http://hobbymolding.com/modules.php?name=Forums

Another choise might be the plastics forum

http://www.plastics.com:/forums/index.php?sid=ae301abf5bd00c75cd66f046b0f8bf09

You are not likely to find someone who will see you as a competitor allowing you to use his tools. Luckly the price of a die for something like this would only be about $300. I would suggest a fiberglass pultrusion like they make kids bike flag antenas out of. Finished cost of the product would be about $2.00 per pound in reasonable quanities.

 

[jplot]

Dwightdixon,

Your note is much appreciated and I assure you no bad mouthing was intended. Over the many years I have been around I have simply developed my own way of doing things and have had enough success to not particularly want to change.
I have been to many web sites where model rotor blades are offered and in every instance they are very expensive and one of the reasons for that is that they all incorporate the 25 percent balance rule and with my design that is simply not needed and I feel that if I could extrude the right kind of plastic I could get a useable rotorblade at a very reasonable price and your note seemed to indicate that. But I must admit that until I do it I really will not know if it will work. Thanks again for your suggestions and I will look into those forums you mentioned.


jvp

 

[dwightdixon]

Since you do not have any knowledge of the engineering properties you need for your design of a auto gyro blade we can not suggest a thermoplastic material that will meet your needs other than what other auto gyro people have used. Real gyro blades are made from carbon fiber layups with expoy resin binders. Fine for the military. They do not care what it costs. Pultrusion polyester fiberglass can be made much cheaper and has excellant properties in pultruded direction. Torsional modulus will be lower than 3 dimensional layup carbon fiber. you will have to compensate for this in your design. Thermoplastic extruded long glass reinforced nylon,acetel,polyester or other engineering polymers will have poorer properties than the pultruded product because the glass is discontinous. You might make up for that in the design but you will surely have to compromise performance. Real blades have a different pitch at the base than at the tip because the linear speed of the blade changes as you move out from the center. That is why any consistant pitch propeller blade, as would be produced by an extrusion, will lack the performance of the real thing. I do not know if your idea is patentable but if it really can perform, I would patent it before I would reveal any more details on an open public forum.

 

[nbucska]

Jplot:
You can get a provisional patent for <$400.- ,good
for one year. You don't need lawyer but you have
to describe it as completelly as possible. Within
one year you MUST file or lose it.



<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[jplot]

The info given in your last note is of great interest and I will be using it in my future information searches. I long ago started the patent process with a provisional patent and am confident I will end up eventually with a patent that I have filed for but that process takes a good while and especially so when one is doing it on their own. The patent however is not on model rotor design but on a flying machine I call a Rotorkite. If you want to get a better idea of what I am talking about then visit my site at rotorkite.com or members.aol.com/rotorkite. Thanks again.